Sifter



A K C E C Q T.

SIFTER 3 Shees-Sheet 2 Filed May 24, 1958 ATTORNEYS Feh, 27, 1940. T; G. CECKA SFTER Filed May 24. 1938 mm3 f.

5 Sheets-Sheet 5 ATTORNEYS Yto masacres. '21, vum f' vlLil-91.9.2135

*UNITED STATES PATENT or-Flca V -4 Anuman May '24, 193s. serai No. 209,694- l A y This invention relates to improvements in sifters.

lt has heretofore been customary to construct sitters including a plurality of sieves arranged in I vI a vertical tier, and suspending this tierof sieves by means of reeds from an overhead support, and

then driving the sitter by Ameans of eccentric I weights mounted on the sifter to produce circular motion of the same and it has been common prac- 1o tice 'to provide these weights or eccentries in pairs one arranged above andthe other below the tier of sieves. These sifters weregenerally operated at a speed oi' about 175 to 190 revolutions per minute and theweights were disposed l5 so as to produce motion of the sieves in circles of about four inches diameter.

Since sifters of greatly increased capacity and operating at speeds of about 300 revolutions per minute were introducedby me, attempts have 20 been made to apply these higher speeds to sitters suspended from overhead supports and also to operate `such sifters by applying rotary motion thereto at one end only of the sifter housing. It -was found, however, that such attempts resulted g5 in an excessive amount of circular motion of the end of the sifter opposite to that to which the circular motion was applied and that such excessive motion not only interfered with the proper and eilicient sifting of the material but vide a new and improved method of sifting by means of which` greatly increased sifting capacity and speed is attained. l

It is also an object of this invention to provide a sifter of the suspended type capable of operating at speeds of about-300 revolutions per minute, and in which excess movement of the portion of the sifter remote from that to which circular motion is applied, is prevented. Itis also an object of this invention to provide a sifterv fin which Vthe reeds used for suspending the sifter are also employed for preventing excessive move--J ment of any part of the sitter. "A further object oi this invention is to provide a sifter in which the sitter housing is suspended from reeds, and in which the reeds are secured both to the upper and to the lower portion of the sifter housing. Another object is to provide a sifter having circular motion imparted to the lower portion of the housing and having the housing suspended from an 'overhead support by means of iiexible 1'reeds secured to the upper and lower portions of the housing, so that the weight of the housing applies u 'tension to the reeds which in turn enables the correct relationl to each other to form a sifter `the throw or the diameter of the circular motion 'samer' according to particle sizes.

reeds tobetter restrain the upper part of the housing against excessive circular motion.

sievesfram'es form the housing of the sifter. It

is also an object to provide means of improved construction for confining the sieve frames in housing. v

A further object of this invention is to provide vmeans of improved construction for varying imparted to the sifter housing. p Other objects of this linvention will appear 'from the following description and claims.

Fig. 4 is a sectional view, on line 4 4. Fig. 1,25'

showing the top plan view, partly in section, of the sifter housing. Figs. 5` and 6 are fragmentary transverse sectional elevations of the sifter housing respectively on lines 5-5 and 6 6, Fig. 4.

Fig. 'l is an elevation, partly in section, of a sitter of modined construction. Fig. 8 is a fragmentary elevation, partly in section, of an. upperV corner portion of the sifter housing shown in Fig. 7.

The word "sifter as herein employed is intended to ,indicate an yapparatus for sifting, screening, or 4bolting o'ur, feed or other finely divided or granular' materials for separating the The sifter shown in theaccompanying drawings illustrates by way of example one vembodiment of my invention, and it is4 not intended to limit this invention to the particular construction or form of the sifter shown in the drawings. since it will he obvious that my invention is applicable to sifters `of other constructions. The sifter may include one or more sieves or screens of thedesired mesh.

The particular sifxter shown in` Figs. 1 to 6 includes a bottom l0, which is provided with a plurality of discharge ducts il for the material which has been sifted, and a plurality of 'sifter A frames I2 are arranged -ina vertical tier abovel the bottom III. Above the uppermost of these sa frames may be provided with the usual dust-tight` gaskets (not shown). The walls of the sieve frames may be held in correct relation to each other in any suitable or desired manner, and in order to avoid the use of any outer wail or casing for confining the sieve frames in correct relation to each other, I preferably provide each sieve frame at the corners thereof with angleshaped members or corner pieces I1 which extend beyond the upper or lower edges of' the sieve frame so as to overlap portions of the corners. of an adjacentV sieve frame. In the construction shown, the corner pieces I1 are secured to the sieve frames I2 in such a manner as to extend slightly below the lower edge portions of each sieve frame, and consequently, to engage the adjacent upper corner portions of the next lower sieve frame. The lowest sieve frame I2 may be held in correct relation to the bottom IU Iin some other manner, for example, by means of an upwardly extending outer ange I8, so that the lower sieve frame has no corner pieces 11. The top member I4 of the sifter housing is also provided with corner pieces or brackets 20 of somewhat larger size-which overlap the corners of the top sieve frame I2.

In addition to beingheld in correct vvertical alinement with relation to each other, means are preferably also Lprovided for securing the sieve frames and the top and bottom of the sifter housing against vertical displacementA relativelyv to each other. Any suitable. means may be provided for this purpose, and4 in the construction shown, an upright bolt or tie rod 22 is provided A at each corner of the sieve housing, which extends through holes in the sieve frames I2y and in the top and bottom members I4 and I0 of.

the sifter housing. These tierods may be releasablyheld in place by means of nuts 24 having threaded engagement with thev lower ends of the tie rods.

As a result of the construction described, any or all of the sieve frames can be easily removed from the apparatus by releasing and removing the tie rods. Consequently, the sieve frames can be easilyremoved for cleaning, or the sieve frames can be replaced by others having sieves of different mesh. Also sieve frames with broken-sieves can be quickly removed and replaced. It will also be obvious that the numberof sieve frames may be varied according to the needs of the user of the machine by merelyproviding tie rods of the of the sifter housing, for example, on the lower end, as has heretofore beenfrquently done, or if desired, such circular motion may be applied to the sifter housing by means of a crank or eccentric rotatably jurnalled on a suitable base arranged below the sifter housing. The latter v construction is illustrated by vway of example in the accompanying drawings, in which 25 represents ay base which may be secured to the floor below the sifter housing, and which has a cenaromas sieve frames is a top member I4 provided-withj traf upwardly extending hub portion 21 in which an upright rodor shaft 23 is journalied'in any suitable or desired mannen This shaft is lrigidly connected with a. crank pin or eccentric 29 which is journalled in a self-alining bearing 30 suitably secured to the bottom member I0 of the sifter housing. 'I'he upright shaft 28 may be rotated in any suitable or desired manner, for example, by means of a pulley 3l and belt 32 connected with any-suitable driving means (not shownY. Because of the eccentricity ofthe crank 29 and the forces acting thereonfthe pulley 3| is preferably provided with a suitable counterweight 33, as has heretofore been common practice, to reduce vibration of the shifter. n

From the foregoing description, it will be obvious that when the shaft 28 and crank 29 are rotated, a circular motion will be imparted to the bottom of the conveyor` housing. If the speed of this circular motion is materially increased over the4 speed of about 175 revolutions per minute, which was heretofore commonly employed, the manner of supporting theshifter housing heretovfore employed is inadequate in that the upper part of the sifter housing would tend to swing about a much greater radius than the radius about which circular motion is imparted to the bottom of the sifter. Consequently, inV orderto' form a suitable support for the sifter housing, I provide flexible supporting means or reeds which are secured to the lower part of the housing to suspend the housing from an overhead sup'- port and I also provide means for resiliently opposing such excessive movement of Vthe upper part of the sifter housing. I have also ,found that this can -be very effectively accomplished by connecting these exible means or reeds with the upper portion of the sifter housing so that the suspending members limit the extent of movevmay be in the form of corner pieces or brackets 31 secured to the bottom member I0 of the sifter housing and extending outwardly therefrom. These clamping members may be similar to those heretofore used in connection with sifters susf pended from overhead supports, and are not herein shown in detail; Similar clamping members 38, whichmay be a part of and extend outwardly from the corner pieces 20 of the upper member I4 of the sifter housing, may be employed for securing the upper part ofthe housing to the reeds 35, but any suitable means, for connecting this part oi' the housing to the reeds vintermediate of their ends may-be employed. The reedssupport the weight of the sifter housing and this weight, consequently, places the reeds under tension. This tension together with the inherent rigidity of the normally straight reeds, yieldingly opposes the tendency of the-upper part of the housing to move in a circle of greater diameter than the lower part of the housing. 'This restriction of the movement ofthe -upper part ofthe housing produces a movement of the screens which results in a greatly increased capacity of each screen. It has been found that 'sitters constructed as herein described have, when used on some materials, materially greater capacity than sitters having their housings mounted on reeds extending upwardly from a base and4 operated at'a speed from about 290 to 310 revolutions per minute with a throw to make a circle from about one and one-half to two inches, de-

WhileI do not know why rapid passage of the tine material through `the I the upper portion ot sieves.

From the foregoing, it will be clear that-my unproven vmeuiod, f sifting material comprises' depositing material to''b`e`sittedon-tlieuippg,.iirltace of the'sieves in the housing, applying to one end ot the housing a motion in a circular direction, preferably at a radius not more than about one inch andv at a speed of approximately 300 revolutions per minute andyieldingly supporting the sitter housing while motion is applied there- ,to in this manner,

tor example, by means ot flexible reeds which are secured to the one end of the housing, for example, the lowex` end, and yieldngly opposing movement ot the other end of the housing so as to prevent movement of the same in a circular path ot materially more than two inches diameter. This part ot the process can be most readily carriedout by means ot a v connection between said other. end ot the housing with the iiexible reeds or supporting means so that they coniine and lrestrict the motion 'of the housing. My improved method also includes the application ot the weight ot the housing andthe parts connected therewith to the reeds so that the tension thus placed on the reeds will assist in confining the movement ot the upper portion ot the housing. Ashas been stated, this method of sifting resuits in avery high capacity of the sitter and in a rapid pusing ot the material through and over. the sieves.

In sitters of this type, it may be desirable at times to provide the sitter with means tor varying the throw of the lower part ot the sifter,'since with different materials, different movementsior throws are required to produce the maximum capacity of the sitter. This variation in throw may, of course, be obtained by providing va different crank pin, or if desired, an adjustable crank pin may be provided. An' arrangement of this kind is shown inFigs. 2 and 3, in which the upright rod or shaft 28.and the crank pirr 29 are formed in two separate parts, and these two parts are connected in such a wayas to permit one to be adjusted relatively tothe other. For this purpose, I provide at the upper'end ot the upright shaft 28 a part v4I) ot enlarged diameter. This enlarged part has a transverse slot 4i formed therein. The crank pin 29 is formed with a base 42 in the shape of a rectangular bar adapted to iit into the slot 4I and to extend beyond the ends ot' the slot. The pulley 8| preferably has an elongated hub portion 45 provided with a longitudinally extending slot 48, the middle portion ot which is of substantially cylindrical form as indicated at 41 to receive the enlarged upper end 40 ot the upright shaft 28. Ihis slot 48 receives y Il the`endsof'the' base 42 of the crank pin 2l and the means for this base length-l ing drawings.

wise of the slot 4l. Any suitable means may be provided :or adjusting the base 42 lengthwise of the slot and for securing the-base. in its adjusted position during the operation ot the apparatus. In the particular construction shown, I have provided a 'pair of wedges 48 and 49 arranged at opposite ends o f the slot 46 and these wedges have inclined faces which are adapted to engage with correspondingly inclined'taces ot the ends of the base member 42. Consequently, it will be obvious that it one of the wedge members is moved upwardlyA while the other is moved downwardly, the base 42 will be moved iengthwise of the slots 46 and 4 I Consequently, by adjusting the wedges in this manner, the crank pin 29 may be moved toward and from. the vertical axis ot the upright shaft 28 to the desired extent, thus changing the diiirilmeter ot the circle of movement of the crank D their adjusted positions in' any suitable or deextend through holes in the hub portion of the pulley- 3l and which have threaded portions engaging in correspondingly threaded holes in the wedge blocks 48 and 49. Consequently, by means4 M of the bolts 5l and 52, the wedge blocks E8 and 49 may be adjusted as desired and also rigidly secured in their adjusted positions by tightening hoth adjusting screws. This construction also avoids the necessity ot providing a key tor connecting the shaft 28 with the pulley 3|, since the base 42 of the crank pin engaging the slotted portion ot the-upright shaft 28 and in thel slotted portion 46 ot the hub serves to form a driving connection between Ythe pulley 3| and the lupright shaft 28. Any other means for adjusting the throw of one end ot the sitter housing may be employed in place ot that shown, or if desired, a drive shaft as heretofore employed, having a crank pin formed integral therewith may be provided to produce a iixedthrow for the lower end ot the sitter housing. It will also be obvious that while I have shown the sitter housing actuated by a positive drive mounted on a fixed base, yet an eccentric weight may be provided on the lower end of the housing for producing the desired circular movement of the lower end of the housing, such as has heretofore been frequently usedtor imparting motion' to sitter housings. When 'such eccentric weights are employed, it is necessary, however, to provide weights-of suchsize and so positioned relatively to the sitter housing that the lower end of the sitter housing will move*l approximately in a circle of from one and one.

half to two inches diameter, and this throw is also desirable when the circular motion is imparted to the lower end of the sitter by means of a crank or eccentric as shown in the accompany- This throw of the lower end oi. the sitter housing is essential to the high capacity 'of the sitter when driven Aat approximately 300 revolutions per minute.

In Figs. 4 to 6,- I have shown Vby way of example, some sieves which may be employed in connection with my improved sitter housing. cThese sieves may be similar to those shown in my copending application Ser. No. 87,198 filed -June 25,v 1936, or may be of any otherisuitable or desired construction. Briey stated, each sieve has an inner sieve supporting frame 55 arranged within the main or outer sieve frame I2. To the upper edges o t the inner sieve supporting trame,

. izo 'Ihe wedge blocks 48 and 48 may be locked in' 4 i. a screen or sieve 6B ofthedesired screening material may be secured. Preferably, the inner sieve supporting frame 55 includes a partition or dividing'rwall 51 extending cempletely across the interior o1 each frame IZ/ and separating the sieve into two separate parts, and when the sieve frames I2 are arranged `one above thev other, these upright partition walls 51,- ln cooperation with similar walls 58 of the upper frame member I 4 completely divide' the interior of the sitter housing into two halves, each of which may be slipplied with dierent materials through the exme tubes ls, or if desired; the same material may be discharged through both of the tubes I5.

` Below each sieve 55, there is preferably provided a coarse wire screen 59 upon which the usual cleaning brushes (not shown) may be'supported which move along the undersurface oli the screens 56 to prevent plugging of the same.A Below each coarse mesh screen 59, there is pro-` vided an imperforate deflector plate or tray 60 upon. which material' which has passed through the sieve 56 drops. Y Each of the inner sieve frames is so arranged within the outer sieve frame I2 as to be spaced on three sides thereof from the corresponding )three 'sides of the outer sieve frame, the fourth side of the inner frame being secured directly to the outer frame I2. The inner sieve frames vare also arranged in staggered relation to each other, as shown inliig. 5, so that material discharged from the upper surface of the screen 56 of one.y inner sieve frame drops through a space 62 between this inner sieve frame, and the outer sieve frame I2 upon the sieve of the next lower frame. The material to be sifted is,'consequ ently, cascaded from one sieve to the next and some of thisv material may, consequently, pass over all of the sieves of the sifter housing, but if desired, the sieve frames may be readily constructed and arranged so that each sieve or any group.. of sieves operates independently of the other sieves.

At opposite sides of the machine, the inner sieve framesare spaced from the outer sieve frames to form a series of vertically alined spaces 5 which form upright passages 83 into which the material which has passed through the sieves 56 is discharged. This is preferably accomplished by providing each inner sieve frame at opposite sides thereof with slots 64 arranged between the deilector plate or tray 60 and the coarse wire screen 59, see Fig. 6, so that the material which has passed through the sievesis discharged from each sieve frame downwardly through the upright passages 65 and is carried from the sifter 55 through one pair of flexible tubes or ducts I I, as shown in Fig. 6, while `the coarse material which has not passed through the sievesis discharged through the other sets of sleeves or ducts II, as shown in Fig. 5. Sieves of any other suitable or 6 desired form may, of course, be employed in place of those described. 66, Figs. 4, and 6 represents carrier nights in the form of short plates or vanes arranged above each sieve at one side thereof to ldeilect the material across the sieve 65 toward the discharge end thereof during the motion of the sieve housing. Preferably, these' carrier flights are secured to each sieve frame below the tray 60 thereof so that, when the sieve frames o are assembled,`the carrier Iiiights oi' one sieve frame will be above the sieve or screen 56 of the next lower sieve frame.

In Fig". 7 and 8, I have shown my invention applied to a sifter having a different form of hous- .u ing, including an outer shell or box 10 within control the motion of the upper sieves.

aromas which-thevarious sieve frames 69 are arranged. The side walls oi' the box 10 are rigidly secured to the bottom plate 1i ofthe sifter housing and suitable braces 12 may be provided for reinforcing the upper portion ofthe sieve box or outer 6 housing. Infthis case, the sieve box or outer housing is also provided at opposite ends thereof with suitable brackets 14 and 15 extending outwardly, preferably frorn the corners thereof and to which the upright reeds 16 may be secured. 10 In this sifter, the sieve frame's'69 vmay be clamped together by vertical pressure in any suitable manner. For example, an upper plate 11 may be provided at intervals with ysuitable-brackets 18 secured thereto and having portions thereof exl5 tending outwardly beyond the outer shell or housing 1li. `Preferably, these portions of the brackets extend above the brackets v18 and clamping bolts 19 suitablysecured to the corner brackets 15, as

clearly (shown in Fig. 8, and may pass through 20 holes in the brackets 18 of the top plate 11. Each bolt 19 has a clamping nut 80 engaging a bracket 18 to apply pressure tov urge the top plate 11 downwardly against the sieve frames 69, and thus clamp these sieve frames against the bottom 1I of 26 the outer -housing or box of the sifter. l

A While the siftenhousing construction disclosed in Figs. 7 and 8 operates very successfully in connection with myv improved sifter and is preferable to the structure shown in Figs. 1 to 6 from the 30 standpoint of absolutely preventing escape ofdust and protecting the sieve frames against damage, yet for many purposes, I prefer to lemploy the` sitter housing "construction shown in Figs. 1 to 6, in which the outer housing or sifter 35 box is entirely eliminated. The construction shown in Figs. 1 to 6, therefore, not only'reduces the weight of the sifter housing, but also v' renders the individual sifter frames I2 much more readily accessible and eliminates the hous- 40 ing of insects or other vermin between the outer housing and the housing formed by the outer walls of -the sieve frames I2. By nesting these sieves one upon another, as shown in Fig. 6, and then clamping them tightly together, it is very easy to dismantle the complete machine so that the sieves can be easily brushed or otherwise thoroughlyA cleaned.

In addition to the advantages already stated, the sifter herein described has the further advantage that the same is adaptable for use in connection with a large variation in the number of sifter frames which may be employed. It is possible to operate the sifter with only a single sieve or' screen, and if desired, as many as I1 or 55 more such sieves can be employed. Such a large number of sieves cannot be used with sifters supported from a base by means of exible reeds as described in my aforesaid copending application, since the sifter housing then becomes too topheavy. In sifters in which, the sieve frames are supported from the base, if too many sifter frames are supported one above the other, the column becomes so high that it is impossible to y With the construction herein described, however, it has been found that the movement of the upper end of the-sitter housing is not much different when a large number of sieve frames is employed, than it is when a smaller number yis used. This is undoubtedlydue to the restraining inuence 'of the reeds which engage both the upper' and lower end of the housing, and since this restraining inuence is due to some extent to the Weight of the sitter, which tends to draw the reeds intotraight 15 lus line positions, it will be obvious that when a large number of sifters' is employed, the correspondinga sieve upon which material'to be sifted is de' 'a sieve 'upon which material to be sifted is deposited, and which is located intermediate of the upper and lower ends of said housing, means for imparting rotary motion to the lower end only of said sieve housing, iiexible supporting means each connected at its upper end to an overhead holding means and at its lower end to the lower portion of said housing, and means for vyieldingly i opposing movement of the upper portion of said housing to restrict the same to movement not materially greater than the motion imparted to the lower end of said housing.

3. A method of sifting material, which comprises disposing a sieve between the upper and lower ends Vof a housing in a position to support material to be sifted on its upper surface, depositing material to be sifted on said upper surface, applying to the lower end of said housing a motion in a circular path, yieldingly supporting the lower end of said housing, and yieldingly confining the movement of the upper portion of said housing to a circular path not substantially greater than said iirst mentioned circular path.

4. A method ofsifting material, which cornprises disposing a sieve between the upper and lower ends of a housing in a position to support material to be sifted on its upper surface, de-

positing material to be sifted on said upper surface, applying to the lower end of said housing a motion in a circular path, yieldingly suspending the lower end of said housing, and restricting the movement of the upper end of said housing by connecting the same with the means for suspending the lower part of said housing.

5. A support for a sifter housing, which contains' av plurality of sieves arranged, one above another and which has circular movement applied thereto at` one end only, said support including a plurality of reeds suspended at their Jupper ends and connected with both the upper and lower portions of said housing, the'connection of said reeds with the-lower portion of said housing placing the weight of said housing on said reeds.`

6. A support for a sitter housing, which contains a plurality ofv sieves arranged one above another and which has circular movement ap plied to the lower end only thereof, sai`d support including a plurality of reeds secured at their upper ends to an overhead holding means and connected at their lower ends with the lower end of said housing to support the weight thereof, the upper end of said housing -being connected with said reeds intermediate of the ends thereof, whereby the reeds resiliently hold the upper end of said housing against movement in a circle of excessive diameter.

7. A support for a sifter housing, which contains a plurality of sieves arranged one above another and which has circular movement applied to the lower end only thereof,` said supportv including a plurality of reeds secured at their upper ends to an overhead holding means and secured at their lower ends to the lower portion of said housing to carry the weight of said housing, and means for connecting the upper portion of said housing with said reeds, whereby the tension on said reeds due to the weight of said housing resists excessive movement of said upper portion of said housing.

y 8. A siiter including a housing, reeds for suspending said housing from an overhead holding means, said reeds being connected with the upper and lower portions of said housing and receiving the weight of said housing through the connection with the lower portion thereof, and means for applying circular motion to the lower portion of said housing.

9. A sifter including a housing, reeds for suspending said housing from an overhead holding means,v said reeds being connected with the upper and lower portions of said housing and receiving the Weight of said housing through the connection with the lower portion thereof, a base mounted on a xed base below said housing and having a crank rotatable about a substantially upright faxis, and means for connecting the lower` end of said housing with said crank for imparting circular motion to the lower end of said housing.

10. A sifter including a housing, reeds for suspending said housingfrom an overhead holding means, said reeds being connected with the upper ing the weight of said housing through the connection with the lower portion thereof, a base rigidly mounted below said housing, an upright shaft journalled in said base and having a crank, a self-alining bearing connecting the lower part of said housing with said crank, and means for rotating said shaft.

11. AA sifter including a plurality of sieves stacked one upon another and having outer walls forming a sieve housing, interengaging means on said sieves which hold each sieve against shifting laterally relatively to an adjacent sieve to hold vsaid sieves against displacement out of their stacked positions and permitting said sieve frames to be separated vertically, a bottom member upon which the stack of sieves rests, a top member resting upon the upper sieve and held against lateral movement thereto and through which material to be sifted passes to said sieves, a plurality of reeds suspended from their upper ends, means for securing the lower portions of said reeds to said bottom member, means on said top member engaging said reeds for restricting lateral movement of said top member and said stack of sieves, and means for imparting motion in a closed, loop path to said bottom member.

' THOMAS G. CECKA.

' and lower portions of said housing and receiv- 

